I want to host my app on an VPS/VPC and am currently leaning towards the AWS EC2 server. I'm looking at the console right now and I see a bunch of services offered like CloudSearch(managed search service) and SES(email sending service).
Considering the fact that I have already written code to do these things (at least for the search) that works locally, do I/should I still utilize these services? If so, why and how?
You do not need to use these services. But there are limits on sending emails from EC2 instances. (http://aws.amazon.com/ec2/faqs/#general , search for Are there any limitations in sending email from EC2 instances?).
If you intent to send huge amount of emails then you want to use SES.